Electromagnetic weak turbulence theory revisited

Abstract

The statistical mechanical reformulation of weak turbulence theory for unmagnetized plasmas including fully electromagnetic effects was carried out by Yoon [Phys. Plasmas 13, 022302 (2006)]. However, the wave kinetic equation for the transverse wave ignores the nonlinear three-wave interaction that involves two transverse waves and a Langmuir wave, the incoherent analogue of the so-called Raman scattering process, which may account for the third and higher-harmonic plasma emissions. The present paper extends the previous formalism by including such a term.

Weak turbulence theory for collisional plasmas

“…The formalism was later expanded to include effects due to processes related to spontaneously emitted fluctuations, which come from discrete-particle effects, both for wave equations and for particle equations [17]. Further extension occurred when electromagnetic waves were incorporated into the formalism, initially without the discrete-particle effects [18], but later by incorporating effects representing spontaneously emitted thermal fluctuations [19,20]. The foundational equations that resulted from these developments were applied for actual applications, mostly related to quantitative analyses of nonlinear processes associated with the beam-plasma instability.…”

Spontaneous emission of electromagnetic radiation in turbulent plasmas

“…The starting point of our discussion is the standard weak turbulence theory in unmagnetized plasmas in which fully electromagnetic interaction is taken into account. 11 The set of equations describe the time evolution and interactions among Langmuir (L), ion-sound (S), and transverse (T) waves, as well as among plasma particles. We assume that the system is in quasi-steady state, @/@t % 0, and that the electrons and ions are distributed in velocity space according to thermal equilibrium velocity distribution functions (VDF)…”

Two dimensional kinetic analysis of electrostatic harmonic plasma waves

“…13. We present here these equations using non-dimensional variables, which are more suitable for numerical analysis…”

“…11 The formalism was subsequently extended to include the effects of electromagnetic oscillations. 12,13 More recently, the electrostatic part of the renewed formalism was further extended to incorporate effects due to binary interactions of particles, leading to a collisional term in the equations for the particle distributions, and to new terms in the equations for the time evolution of wave amplitudes, identified with the physical processes of collisional damping, spontaneous emission of electrostatic waves by binary particle interactions, and effects due to binary particle interactions in the processes of wave scattering. 14,15 The reformulation of the WT theory, which was presented in Ref.…”